Apparatus for automatically printing two faces of an object



L. G. DUBUIT Nov. 22, 1966 APPARATUS FOR AUTOMATICALLY PRINTING TWO FACES OF AN OBJECT Filed April 2, 1965 6 SheetS-Sheet l f Nov. 22, 1966 L.. G. DUBUIT 3,286,624

APPARATUS FOR AUTOMATICALLY PRNTING TWO FACES OF AN OBJECT Filed April 2, 1965 6 Sheets-Sheet 2 FIGZ Nov. 22, 1966 APPARATUS FOR AUTOMATIOALLY PRINTING TWO FACES OF AN OBJECT Filed April 2, 1965 6 Sheets-Sheet 5 L. G. DUBUIT 3,286,624 y L. G. DUBUIT Nov. 22, 1966 APPARATUS FOR AUTOMATIC/ALLY PRINTING TWO FACES OF AN OBJECT Filed April 2, 1965 6 Sheets-Sheet 4 L. G. DUBUIT Nov. 22, 1966 APPARATUS FOR AUTOMATICALLY PRINTING Two FACES oF AN OBJECT Filed April 2; 1965 6 Sheets-Sheet 5 D@ N mm m VE r. @Q I L.. G. DUBUIT Nov. 22, 1966 APPARATUS FOR AUTOMATICALLY PRINTING Two FACES oF AN OBJECT Filed April 2, 1965 6 Sheets-Sheet s Qttovn 25s United States Patent O 3,286,624 APPARATUS FOR AUTOMATICALLY PRINTING TWO FACES OF AN OBJECT Louis Gilbert Dubuit, 60 Rue Vitruve, Paris, France Filed Apr. 2, 1965, Ser. No. 445,093 Claims priority, application France, Apr. 14, 1964, Oct. 7, 1964, 990,551; Nov. 10, 1964,

7 Claims. (Cl. 101--40) This invention relates to the printing of objects, and particularly to the printing of objects having an oval transverse cross-section.

Objects having oval transverse cross-sections, notably bottles and similar containers made of glass or particularly, of plastic, often require printing on their two large longitudinal faces. Such printing is most often carried out by the silk-screen process. n This printing process consists in forcing the printing lnk, with the aid of a squeegee, through a movable silk screen certain regions of which are rendered impermeable to the passage of ink and the remaining regions of which are in the shape of the design to be printed.

The object, having an oval transverse cross-section, which will be referred to hereafter simply as the oval object is generally placed in a cradle or held between the base plate and the tip of a support arbor of a rotatlng unit which causes the oval object to travel beneath the screen in a circular path, which path is perpendicular to the longitudinal axis of the oval object, in such a way that the radius of the path described by the large, longitudinal object face which is being printed is substantially equal to the principal radius of curvature of said face. This koval object face then comes in contact with the printing screen said screen being moved horizontally 1n each a way that said face rolls against said screen without any slippage existing therebetween, while the squeegee, which is mounted transversely to the screen and which is prevented from being displaced horizontally, forces the ink through the screen in the region where it is tangent to the face being printed.

Until the present time the printing of the two large faces of the oval object was carried out in two distinct operations: during a first operation, the oval object was placed in the machine for the printing of oneV of its faces and the ink was allowed to dry; then during a second operation the oval object was placed anew in the machine for the printing of the other one of its large faces. This process was relatively time-consuming and required a drying period between the two printing operations.

Certain processes for performing a continuous printing of the two faces have already been suggested. However these arrangements, which are based on the use of cams to turn the oval object over after the first printing in order to carry out the second printing, require complicated cams which are difficult to fabricate and, more importantly the time required to turn the oval object over, which time is relatively long, is added to the printing time, so that machines employing such a procedure do not have a high production rate.

The present invention has a's a principal object the construction of a machine permitting the printing, in a continuous manner, of the two large faces of an oval object during a single passage through the machine, and

' comprising, for this purpose, two printing stations each comprising, as required for the silk-screen printing process, a silk screen mounted for horizontal movement, a ver- -tically movable squeegee mounted for application against the screen when the latter is displaced, an object support, a rotating device disposed directly above the support and "ice the oval object at the first station after one of the objectifaces have been printed and to carry it to the second station for the printing of its second face.

According to a preferred embodiment of the invention; the transfer means comprises a fork arrangement which is shaped to receive the oval object and which is given an alternating, arcuate movement between the two stations, said movement being effected in synchronism with the movements of the screens.

The transfer means of the present invention are particularly simple and can easily be adapted for use with a wide variety of printing apparatus similar to the one described above. Moreover, since a succeeding oval object can be placed in position to have its first face printed while the preceding object is being transferred to the second printing station, a machine equipped with the present invention can turn out objects having both faces printed at almost the same rate as a machine which prints only one face. Furthermore, since both faces of each object dry at the same time the drying time for each object printed according to the present invention is cut substantially in half.

Another object of the present invention is a machine of the type described above in which the object supports are driven horizontally, by means of an endless conveyor, below the printing stations in a direction parallel to the separation between the two printing stations, and in which said conveyor carries, in association with each of said supports, at least one holding means for maintaining the object in position on its support during its period of travel on the conveyor.

Such a holding means presents the advantage of maintaining the oval object precisely in the desired position on the conveyor, with the result that the speed of said conveyor, and hence the production rate of the machine, can be safely increased, the oval object always arriving in its correct position beneath the printing stations.

It is a further object of the present invention to provide various other improvements for machines of this type.

In order to realize one of these other improvements, there is provided, for each printing station, a rotating l device comprising a base plate mounted for ratation about a first axis, and a support arbor which is placed opposite said base plate and which is movable in a direction parallel to the axis of rotation of said base plate for forcing and holding an object against said plate, said arbor being mounted for rotation about a second axis which is separate from said first axis, said two axes being aligned with onelanother, and said plate and said arbor being rotated in synchronism with one another. Such an arrangement permits the printing of objects having a wide variety of dimensions.

According to another one of these improvements, the vertical displacement of the squeegees is obtained` in a particularly simple manner.

These and other objects, features and characteristics of the present invention will become more readily apparent from the following detailed description when taken together with the accompanying drawings, in which:

FIG. 1 is elevation view of a machine equipped with one preferred embodiment of the present invention.

FIG. 2 is a top View of the machine of FIG. 1.

FIG. 3 is a cross sectional view taken along the plane III-III of FIG. 2.

FIG. 4 is an elevation view of a portion of a continuous conveyor chain carrying an oval object held by one embodiment of the holding means of the present invention.

FIG. 5 is a side view of the structure of FIG. 4.

FIG. 6 is a cross-sectional view taken along the plane VI-VI of FIG. 5.

FIGS. 7 to 9 are views analogous to those of FIGS. 4-6, respectively, showing the oval object released by said holding means; and

FIGS. and 1l are views similar to those of FIGS. 1 and 3, respectively, showing a modified version of the device of FIGS. 1-3.

FIG. 1 shows a silk-screen printing machine similar to that shown and described in French Patent No. 1,263,239, led by the present applicant on February 23, 1960. This machine is essentially formed by a carriage constituted by two vertical arms 1 and 1 which slide on cylindrical horizontal bars 2 and 3 and which carry a rectangular bar 4 which is also horizontal and to which are attached arms 5, 6 and 7 carrying silk-screens 23 and 24. To bar 4 there is also attached a yoke 8 (see FIGS. 2 and 3) terminated by a fork 9 in which is engaged a finger 10, said finger being rigidly connected to a carriage 11 which is slidably mounted on a horizontal bar 26. This carriage 11 carries a cylindrical body surrounding bar 26 and a vertical plate 11A having a groove cut in its rear face to form a vertical slide 11B. Carriage 11 is given an alternating movement by a roller 12 engaged in slide 11B and mounted on a disc 13, at a predetermined distance from the center of rotation thereof, for rotation therewith. The disc is driven in rotation by the output shaft of a speed reducer 14 whose input shaft 15 is driven by a pulley 16 which is in turn driven by a motor (not shown). The input shaft 15 is extended (see FIGS. l and 2) by a shaft 116 which, through the intermediary of universal joints, drives another speed reducer 17 similar to speed reducer 14. On the output shaft 18 of speed reducer 17 is attached a pinion gear 19 which engages a pinion gear 20 rotatably mounted on the machine frame and to which is rigidly connected one end of a shaft 21. The other end of shaft 21 carries a rigidly connected cam 22. The mechanical power transmission is so arranged that cam 22 rotates in synchronism With the silk-screens.

In the embodiment of FIGS. l to 3, the screen supporting carriage is given, in addition to its longitudinal alternating movement, a vertical movement. In order to permit this to be accomplished, the two bars 2 and 3, upon which arms 1 and 1 slide, form a deformable parallelepiped with two fixed horizontal bars 25 and 26 which are vertically spaced from one another. The bars 25 and 26 are held between two end plates 27 and 28 of the machine frame. At respective ones of their eX- tremities, bars 2 and 25 are connected together by arms 29 and 30, both ends of which arms are pivotally connected to their respective bars. Similarly, bars 3 and 26 are connected together by pivotally mounted arms 29 and 30 (see. FIGS. 2 and 3). Arm 30 carries an extension 31 upon which is pivotally mounted one end of a vertical connecting rod 32, the other end of which is pivotally connected to the free end of a lever 33. The other end of lever 33 is pivotally connected to the machine frame at 33A (see FIG. 2). Lever 33 carries a roller 34 which rolls against the rim of disc 13. This rim carries at least one boss 13A which causes the disc to act as a cam driving roller 34 and hence causing -lever 33 to ivot. p As is shown in FIG. 2, a sleeve 35 rotates around the central region of bar 25. Sleeve 35, which may be restrained from longitudinal movement, is rigidly connected to an arm 36 which is mounted in a pivotable manner on bar 2. Arm 36 carries (see FIG. 3) an extension 41A to which is pivotally connected, at 37, one end of a vertical arm 40 destined to support the squeegees. At its lower end, arm 40 is pivotally connected, at 38, to an arm 41 which can rotate on bar 3. This assembly constitutes a deformable parallelepiped which functions to elevate the squeegee-carrying arm 40 more rapidly t'han the screen-carrying arms 5, 6 and 7 when, under t-he camming action of disc 13 on roller 34, the lever 33, acting through connecting rod 32, pulls the extension 31 of arm 30 downwards. When this occurs, arm 30 pivots around fixed bar 25 and displaces, on the one hand, bars 2 and 3 and hence the screens and, on the other hand, squeegeecarrying arm 40, the latter being vertically displaced by a greater amount than the former.

In accordance with the present invention, the abovedescribed machine comprises two printing stations, i.e. two silk-screens 23 and 24, as has already been noted, and two squeegees 42 and 43 carried by arm 40 and situated above screens 23 and 24, respectively. In addition, beneath screen 23 are disposed a support 44 for an oval object, which support could be carried by a conveyor chain, and a disc 45 whose supporting shaft 48 rotates in a hub 46. The hub 46 is carried by a fork 47 which is designed to permit the hub elevation to be varied at will (see FIG. l). At one of its ends, shaft 48 carries a' pinion 49 engaging a toothed rack 50 rigidly mounted on slidable carriage 11. The radii of pinion 49 and disc 45 are made equal to the principal radius of curvature of the large oval object face to be printed at this first printing station. At its other end, shaft 48 carries an arbor supporting an object engaging tip 51, the distance separating the tip from the shaft being variable and the arbor being mounted to be driven in rotation by the shaft so that the tip 51 revolves about shaft 48. This tip 51 is mounted to be displaced in a direction parallel to the axis of shaft 48 by the action of a pneumatic jack 51A controlled by the rotation of a cam 70 rigidly connected to the output shaft of one of the speed reducers (see FIGS. 2 and 3). The assembly of plate 45, tip 51, and their respective driving means forms a rotating device intended, as will be described below, to carry an oval object, originally resting on support 44, along a circular path so as to bring the large face to be printed into rolling contact with screen 23.

Similarly, the second printing station comprises a screen 24, a squeegee 43, a support 54 for the printed object, and a rotating device constituted principally by a disc 55 whose driving shaft 58 turns in a hub 56 carried by a fork 57, the fork being designed to permit variations to be made in the hub elevation, and a pinion gear 59 rigidly connected to one end of shaft 58 and engaging the toothed rack 50 of carriage 11.

In accordance with a principal feature of the present invention, a machine of the type described above is equipped with a transfer device disposed between the two printing stations. A preferred embodiment of this device is shown in FIGS. l-3 as comprising two forks 67 and 68 (FIG. 3) carried at the free end of a transfer lever 65 whose other end is pivotally mounted, at 66, on the machine frame. A connecting rod 60 has one end pivotally connected, at 64, to lever 65 and its other end pivotally connected, at 61, to one end of control lever 62. The control lever is pivotally mounted, at an intermediate point 69, on the machine frame and carries, at its other end,l `a cam follower wheel 63 which is driven by cam 22. Wheel 63 is maintained in contact with said cam by means of a tensed restraining spring 72 connected between the machine frame and transfer lever 65. The dimensions of the levers 65 and 62 and of cam 22 are so chosen that a full rotation of the cam pivots lever 65 from a first position in which forks 67 and 68 are inthe region of the rotating device of the rst printing station to a second position (shown in dot-dash lines in FIG. l) in which the forks are in the region of the rotating device of the second printing station.

The machine functions in the following manner:

l Cam 13 is rotated into a position in which its camming action on follower 34 causes the screens and squeeezanga-1 gees to move into their raised positions, and an oval object 52 to be printed is placed on support 44.` Disc 13 is then rotated to cause the screens and squeegees to be lowered and at lthe same time cam 70 causes jack 51A to force tip 51 against one end of object 52, wedging the object between this tip and base plate 45. Base plate 45 could preferably be formed with a recess for receiving the base of object 52.

The continuous rotation of disc 13 acts, through the intermediary of roller 12 engaged in slide 11B, to displace the screen-carrying carriage and carriage 11 in unison and this movement causes rack 50 to rotate shaft 48 in such a way as to cause the rotating device to rotate object 52 into contact with screen 23 and to cause the large oval object face A to roll on screen 23.

The dimensions of the various driving elements are so chosen that the rate of rotation of object face A is in synchronism with the velocity of displacement of screen 23 so that there is no slippage between screen 23 and face A and hence a sharp print is produced on the latter. Simultanesously with this rolling motion, squeegee 42, which is disposed substantially in line with the line of contact between the screen and surface A, forces the printing ink through the screen, causing face A to be printed.

Once the entire surface of face A is printed, this face, which is being continuously rotated, moves out of con-f tact with screen 23 and arrives in a position, as shown in solid lines in FIG. 1, in which it is cradled in forks 67 and 68 of transfer lever 65. At this instant cam 70 actsI on jack 51A to retract tip 51 and cam 22 rotates into a position where it causes lever 62 to pivot into the `position shown in dotted lines in FIG. 1. This movement of lever 62 is transmitted, by rod 60, to lever 65 to cause the latter to rotate into its second extreme position, also shown in dotted lines in FIG. 1, in which it places oval object 52 in the path of rotation of the second rotating device (elements 55, 71, etc.) in such a Way that its second large face B will be in printing position. `During this time, the screens have arrived at the end of their advance travel and the continuing rotation of disc 13, returns them to the left, for printing the face A of a new object.

The rotation of the second rotating device is so synchronized with the movement of lever 65 that tip 71 is at` this instant in position to grip object 52. Cam 70 then causes a second jack (not shown) to extend tip 71'y so as to cause object 52 to be held between this tip andl base plate 55, the second rotating devices continues to` turn and screen 24 once again begins moving to the right, and face B comes into a rolling contact with screen 24 while squeegee 43 forces ink through the screen, causing face B to be printed. Thus both faces have been printed during one pass through the apparatus.

Finally screens 23 and 24 once again reach the righthand end of their travel path (with respect to the views of FIGS. l and 2), object 5,2 is deposited on support 54,- tip 71 is retracted. and the object may be removed for drying- Disc 13 continues to rotate. returning the carriages, screens and rotating devices to their initial positions (placing the carriages and screens and the left-hand end of their travel paths) in preparation for receiving a new object to be printed.

The printing of a succession of oval objects may be rendered at least semi-automatic, according to another feature of the present invention, -by causing the two supports 44 and 54 to be carried on a conveyor chain which is moved beneath the screens in a direction and parallel to the direction of screen movement. The displacements of this chain may be maintained in perfect synchronism with those of the screen by causing the chain to be driven, for example, by a Maltese cross (not shown) driven by a crank pin keyed lto shaft 21. One half of each cycle of rotation of the crank pin corresponds to the advance travel of screens 23 and 24 and the second half of each such cycle displaces the chain and corresponds to the return travel of the screens. It is therefore desirable, as has been mentioned above, that the objects be firmly held in position on their respective supports.

FIGS. 4 to 9 show one embodiment of an object holding device which fulfills these conditions.

As shown in these figures, the conveyor chain is constituted by a parallel pair of simple chains and 80' each of which is formed, in a well-known manner, by a succession of links.

Each ling of chain 80 comprises two pins 82 and 83 to which is attached a plate 81. The plate 81 of one of the links carries, by means of a screw or bolt 85, an oval object support 44 while the plates 81 of the two links adjoining said one link are fastened, by means of screws or bolts 85, to auxiliary supports 86 and 87, respectively. A first object positioning post is pivotally connected to support 86 by means of a pivot pin 88 and a second object positioning post 91 is similar-ly pivotally connected to support 87 by means of a pivot pin 89. The base portion of post 90 is formed with an arcuate stud slot 93 through which extends a finger 92 carried by, and extending normally from, the base portion of post 91. Finger 92 is positioned so that its lateral surface rides upon a guide bar disposed parallel to chain 81. The upper surface of bar 95 is formed with a descending ramp 95A disposed directly below the first printing station and an ascending ramp 95B disposed directly below the second printing station.

In an identical manner, each -link of chain 80 carries a plate 81' attached to the two link pins 82 and 83. One plate 81 carries an oval object support 44 which is disposed opposite support 44. One of the plates 81 adjacent said one plate 81 carries a pivotally mounted oval object positioning post 91 from the base of which a linger 92 extends perpendicularly, while the other one of plates 81 adjacent said one plate 81 carries a pivotally mounted oval object positioning post 90' whose base portion is formed with an arcuate stud slot 93 through which finger 92 extends. A guide bar 95 is disposed beneath, and parallel to, chain 80 in such a way as to permit the lateral surface of finger 92 to slide therealong. Bar 95 is formed with a descending ramp 95A directly below the first printing station and an ascending ramp 95B directly below the second printing station. In a general manner, the assembly associated with chain 80 is identical with that of chain 80 and each element of the former as sembly carries the same principal reference number as the identical corresponding element ofthe latter assembly. Although, for the sake of simplicity, only the operation of the assembly associated with chain 80 will be described in detail below, it should be understood that the assembly associated with chain 80 functions simultaneous-ly with, and in exactly the same manner as, the assembly of chain 80.

As the chain 80 advances, finger 92 slides along the upper surface of bar 95. As long as the finger is in contact with the guide portion a head of ramp 95A, it

' serves to maintain posts 90 and 91 in a closed position where they bear against, and thus assure the accurate positioning of, the oval object resting on supports 44, 44 as is shown in FIGS. 4 and 6. When finger 92 reaches ramp 95A, it is permitted to descend, thereby permitting, due to the presence of stud slot 93, the two posts 90 and 91 to pivot under their own weight into an object releasing position until reaching the fully open position of FIGS. 7 and 9 when finger 92 reaches the lower end of ramp 95A. Posts 9i) 4and 91 are then clear of the oval object and the latter is in position to be gripped by the rotating device of the first printing station, shown in FIGS. 1-3. The oval object then goes through the previously described printing process and is brought t0 the lowest point in the path of rotation of the rotating various driving and control elements of the apparatus and i by the fact that all of the moving parts are driven from a single input. As soon as the printed object is deposited on supports 44, 44', the object is released by the gripping means of the second rotating device and finger 92 rides up ramp 95B, causing posts 90 and 91 to pivot back into contact with the edges of the oval object.

It may be noted that the object bearing surfaces are inclined and have an upwardly convex cross-section. Such a form assures that the printing on the object faces will not become smudged or smeared before having had a chance to dry.

FIGS, and 11 show a machine containing certain modifications of the structure of FIGS 1-3. In FIGS. 10-11, certain elements common to the structure of FIGS. 1-3 have not been shown in one or both gures for the sake of simplicity and other elements common thereto have been shown without reference numerals for the same reason.

One of these modifications is intended to extend the size range of objects which can be printed by permitting the handling of objects whose thickness (i.e. the distance separating the centers of its two large faces) would prevent them from being positioned in the rotating devices of FIGS. 1-3.

To this end, the rotating devices (FIG. 1l) have been modified by replacing the shaft 48 of FIGS. 1-3 by a shaft 481, which only extends from pinion 49 to plate 45 and by providing a second shaft 148, coaxial with shaft 481, which is mounted for rotation in a hub 146 and one end of which carries the tip 51 the latter being fast for rotation with shaft 148. This arrangement permits the rotating device of each printing station to handle an oval object whose thickness is such that a portion of the object extends through the longitudinal axis of the rotating device (i.e. when the thickness of the object is greater than the principal radius of curvature of the large face to be printed).

Tip 51 is driven by means of a toothed" rack 150 engaging a pinion gear 199 keyed onto shaft 146. Rack 150 is carried by screen-carrying arms 5, 6 and 7 and is parallel to rack 50, while rack 150 and gear 149 are identical in size and tooth pitch with rack 50 and gear 49, respectively. Therefore, disc 45 and tip 51 will always rotate in synchronism.

It should be understood that the above description applies equally well to the rotating device associated with the second printing station.

Another modification is based' on the fact that, since the oval object moves out of contact with the screen at the end of each printing operation, it is possible to suppress the vertical movement of the screens. On the other hand, squeegees 42 and 43 must continue to be vertically movable so that they can be raised during the return travel of the screens.

In accordance with these considerations, the means for deforming the parallelepiped constituted by bars 2, 3, 25 and 26 and arms 29, 29', 30 and 30 are eliminated, and the squeegees 42 and 43 are each carried by a respective one of arms 102 and 112 each of which is pivotally mounted on arm 40 for independent movement about a respective one of the horizontal axes 103 and 113. Arm 102 carriers a cam follower 104 and arm 112 carries a similar cam follower 114. These followers roll on a carnming surface formed on a guide bar 105 rigidly connected to the screen-carrying carriage and disposed parallel to the travel path of said carriage. That carriage also carries two arms 106 and 107, pivotally mounted at 8 108 and 109, respectively, in such a way that these arms travel with the carriage and remain disposed above the depressions 106A and 107A, respectively, in the caming surface of guide bar 105. Both arms 106 and' 107 have tapered ends and are arranged to have a substantially greater length to the left of their respective pivots than to the right thereof, both arms thus tending to pivot counterclockwise when acted on only by their own weight, until their left-hand extremities come in contact with the camming surface of guide bar 105.

When the screen-carrying carriage moves from right to left (with reference to the view of FIG. 10) the rollers 104 and 114 roll along guide bar 105 and then along the upper surfaces of arms 106 and 107, respectively, these arms pivoting in a clockwise direction as the rollers pass pivots 108 and 109, respectively, so as to cause the righthand ends of said upper surfaces of said arms to form a continuation of the fiat portion of the upper surface of guide bar 105. Thus, when the screen carrying carriages move from right to left, which movement corresponds to the return travel of the screens, rollers 104 and 114 never descend into depressions 106A and 107A and, as a result, squeegees 42 and 43 do not come in contact with their respective screens.

On the other hand, when the screen-carrying carriage moves from left to right, the rollers 104 and 114 are permitted to descend under the action of their own weight into depressions 106A and 107A, respectively, the arms 106 and 107 having pivoted back in a counterclockwise direction, the descent of the two rollers not necessarily being simultaneous but being determined by the relative positions of the two depressions. The descent of each roller naturally causes its respective squeegee to bear against its corresponding screen. As each arm 106, 107 continues to move on top of its respective roller, it is constrained to pivot in a clockwise direction so as to permit the roller to eventually move out of its respective depression and back onto the flat surface of bar 105, at which time the arms 106 and 107 are permitted to pivot back in a counterclockwise direction under the action of their own weight.

In the embodiment shown in FIGS. 10 and 1l the arms 106 and 107 and the depressions 106A and 107A are positioned with respect to one another so as to permit the second face of one oval object and the first face of a succeeding oval object to be printed successively during one period of left-to-right travel of the screens. Thus, both rotating devices are in the process of carrying an object and the rotating device (71, 156-159) of the second printing station moved said one object in contact with screen 24 while the rotating device of the first printing station is in the process of bringing said succeeding object towards screen 23.

Among the many Variations which may be employed in the construction of devices according to the present invention, it is of interest to mention that the means for transferring an object from one printing station to another may be driven by a pneumatically actuated carriage instead of by the cam and connecting rod assembly illustrated. In addition, instead of providing two pairs of object positioning means (FIGS. 4-9), it would be possible to employ one pair of such means positioned midway between the base and the neck of the object, and these positioning means could be controlled by any known system of cables or chains instead of by means of cams. Also, the positioning means could be constituted by a pair, or pairs of coaxially aligned jacks arranged to face one another. In place of the rack and pinion arrangement for driving the rotating devices, one may use a friction drive between a bar and a smooth disc, or cabledriven pullies mounted on the shafts of the rotating devices. Finally, the vertical movement of the squeegees could also be accomplished by hydraulic jacks or by electromagnets.

While several preferred embodiments of the present invention, and modifications thereof, have been described above and shown in the attached drawings, it should be appreciated that many other variations and modifications thereto without departing from the spirit of this invention, whose coverage should therefore be limited only by the scope of the appended claims.

What I claim is:

1. Apparatus for automatically printing, in succession, the two large lateral faces of an object having an oval transverse cross section, said apparatus comprising:

(a) two printing stations each arranged to print a respective one of the large lateral faces of such object and each including a rotating device for bringing a respective one of such lateral faces into rolling, nonsliding contact with a printing element;

(b) a transfer device mounted between said rotating devices for carrying said object and including: a lever mounted to pivot about a stationary axis between a first position in which it intercepts such object while it is being carried by one of said rotating devices and a second position in which it places such object in position to be engaged by the other one of said rotating devices; two forks mounted on one end of said lever in spaced relation with respect to one another for receiving such object; a cam driven in rotation in synchronism with said rotating devices; a control lever having an intermediate point in its length mounted on a stationary pivot; a cam follower mounted on said control lever in a position to contact said cam; a connecting rod connecting said lever to said control lever; and elastic restraining means connected to said transverse device for constantly urging said cam follower against said cam, said cam being so shaped that during one full rotation it moves said lever from its said first position to its said second position and back to its first position; and

(c) means for driving said cam in order to move said transfer device between said first position and said second position.

2. Apparatus for automatically printing, in succession, the two large lateral faces of an object having an oval transverse cross section, comprising, in combination:

(a) two printing stations each arranged to print a respective lateral face of such object and each including a rotating device for bringing a respective object face into rolling, non-sliding contact with a printing element;

(b) a transfer device mounted between said rotating devices for carrying such object and including a pneumatically operated carriage mounted to move alternatingly between said two printing stations; and

(c) means for moving said transfer device from a first position in which it intercepts such object while it is being carried by one of said rotating devices to a second position in which it places such object into position to be engaged by the other one of said rotating devices.

3. Apparatus for automatically printing, in succession, the two large lateral faces of an object having an oval transverse cross section, comprising, in combination:

(a) two printing stations each arranged to print a respective one of the lateral faces of such object and each including a rotating device for bringing a respective one of such object faces into rolling, nonsliding contact with a printing element;

(b) a transfer device mounted between said rotating devices for carrying such object;

(c) means for moving said transfer device from a first position in which it intercepts such object while it is being carried by one of said rotating devices to a second position in which it places such object in position to be engaged by the other one of said rotating devices;

(d) a plurality of object supports, each for supporting a respective one of such object in the path of at least one of said rotating devices;

(e) conveyor means upon which said object supports are mounted for moving said supports horizontally between said two printing stations; and

(f) at least one object positioning means associated with each of said object supports and carried by said conveyor means for holding such object in position on its associated support, each of said object positioning means including at least two pivotably mounted posts and control means associated with said posts for moving them between a closed position, in which they grip such object, and an open position, in which they liberate such object.

4. An arrangement as defined in claim 3 wherein said object-positioning means includes two pairs of pivotably mounted posts spaced apart from one another in a direction transverse to the direction of movement of said conveyor means for gripping such object near respective ones of its ends, and said control means are arranged for moving both of said pairs of posts between said closed position and said open position.

5. An arrangement as defined in claim 3 wherein, for each of said positioning means, one of said posts carries a finger extending parallel to the axis of rotation of said one of said posts and the other one of said posts is formed with an arcuate stud slot through which said finger projects, said arrangement further comprising a stationary linear cam along which said finger moves.

6. An arrangement as defined in claim 5 wherein said linear cam is disposed parallel to said conveyor and said upper surface of said cam is formed with a depressed portion extending between said two printing stations for permitting said finger to descend and to thus move said posts into their said open position.

7. Apparatus for automatically printing, in succession, the large lateral faces of an object having an oval transverse cross section, comprising, in combination:

(a) two printing stations each arranged to print a respective one of the lateral faces of such object and each including a silk printing screen, a rotating device for bringing a respective object face into rolling, non-sliding contact with said screen, a squeegee mounted to remain directly above the axis of rotation of said rotating device, a squeege supporting arm having one end mounted for rotation about a horizontal axis and the other end carrying said squeegee and a cam follower mounted on said arm;

(b) a screen-carrying carriage supporting said screens and carrying said one end of each said supporting arm, said carriage being slidably mounted to move said screens in a horizontal direction perpendicular to the axes of rotation of said rotating devices;

(c) a transfer device mounted between said rotating devices for carrying such object;

(d) means for moving said transfer device from a first position, in which it intercepts such object being carried by one of said rotating devices, to a second position in which it places such object in position to be engaged by the other one of said rotating devices; and

(e) guiding means for said cam followers mounted for movement with said screens and including a guide bar upon the upper surface of which said cam followers travel, said guide bar being disposed parallel to the direction of movement of said screens, said upper surface being formed with one indentation for each of said printing stations for permitting said cam followers to descend so as to bring each of said squeegees into contact with its respective screen during a predetermined period of time, said guiding means further including one guide lever for each of said indentations, each said guide lever being disposed above its respective indentation and being mounted to pivot about a point removed from its center of gravity, whereby each said guide lever is References Cited by the Examiner free 'no pivot under the action of its own Weight. into UNITED STATES PATENTS a pos1t1on Where one of its ends forms a continuais thus prevented from descending into its associated ROBERT E, PULFREY, Primary Examiner. indentation and prevents its associated squeegee l from moving into contact with its corresponding DAVID KLEIN Examiner' screen. 10 W. MCCARTHY, Assistant Examiner. 

1. APPARATUS FOR AUTOMATICALLY PRINTING, IN SUCCESSION, THE TWO LARGE LATERAL FACES OF AN OBJECT HAVING AN OVAL TRANSVERSE CROSS SECTION, SAID APPARATUS COMPRISING: (A) TWO PRINTING STATIONS EACH ARRANGED TO PRINT A RESPECTIVE ONE OF THE LARGE LATERAL FACES OF SUCH OBJECT AND EACH INCLUDING A ROTATING DEVICE FOR BRINGING A RESPECTIVE ONE OF SUCH LATERAL FACES INTO ROLLING, NONSLIDING CONTACT WITH A PRINTING ELEMENT; (B) A TRANSFER DEVICE MOUNTED BETWEEN SAID ROTATING DEVICES FOR CARRYING SAID OBJECT AND INCLUDING: A LEVER MOUNTED TO PIVOT ABOUT A STATIONARY AXIS BETWEEN A FIRST POSITION IN WHICH IT INTERCEPTS SUCH OBJECT WHILE IT IS BEING CARRIED BY ONE OF SAID ROTATING DEVICES AND A SECOND POSITION IN WHICH IT PLACES SUCH OBJECT IN POSITION TO BE ENGAGED BY THE OTHER ONE OF SAID ROTATING DEVICES; TWO FORKS MOUNTED ON ONE END OF SAID LEVER IN SPACED RELATION WITH RESPECT TO ONE ANOTHER FOR RECEIVING SUCH OBJECT; A CAM DRIVEN IN ROTATION IN SYNCHRONISM WITH SAID ROTATING DEVICES; A CONTROL LEVER HAVING AN INTERMEDIATE POINT IN ITS LENGTH MOUNTED ON A STATIONARY PIVOTS A CAM FOLLOWER MOUNTED ON SAID CONTROL LEVER IN A POSITION TO CONTACT SAID CAM; A CONNECTING ROD CONNECTING SAID LEVER TO SAID CONTROL LEVER; AND ELASTIC RESTRAINING MEANS CONNECTED TO SAID TRANSVERSE DEVICE FOR CONSTANTLY URGING SAID CAM FOLLOWER AGAINST SAID CAM, SAID CAM BEING SO SHAPED THAT DURING ONE FULL ROTATION IT MOVES SAID LEVER FROM ITS SAID FIRST POSITION TO ITS SAID SECOND POSITION AND BACK TO ITS FIRST POSITIONS; AND (C) MEANS FOR DRIVING SAID CAM IN ORDER TO MOVE SAID TRANSFER DEVICE BETWEEN SAID FIRST POSITION AND SAID SECOND POSITION. 